Mechanism for producing angular movement



Sept. 9, 1941- J. K. SIMPSON MECHANISM FOR PRODUCING ANGULAR MOVEMENT Filed May 9, 1940 2 Sheets-Sheet 1 1+ M Ksm 'm In! 151v 1' on r 18W WM 2 Shets-$heet 2 JOHN K sii' rnpsow In! VtNT AW w 42 Sept- 9, 1941- J. K. SIMPSON MECHANISM FOR PRODUCING ANGULAR MOVEMENT Filed May 9, 1940 Patented Sept. 9, 1941 UNITED STATE S PATENT OFFICE- MECHANISM FOR PRODUCING ANGULAR MOVEMENT John Keith Simpson, London, England, assignor to. Automotive Products Company Limited,

' London, England Application May 9, 1940, Serial No. 334,290 In Great Britain May 6, 1939 4 Claims.

This invention relates to mechanism for producing angular movement, and is illustrated for use in retractable landing gear for aircraft.

According to the invention, a tubular struc-- tural member adapted to move angularly about a pivot is characterised by the feature that the said member forms a cylinder containing a piston, the piston being moved axially within the tubular member to move the latter bodily about its pivotal mounting.

The structural member may be pivoted on a shaft formed with a crank, the piston bei ng coupled to the crank by a connecting ro d{and two pistons may be arranged one on each side of the shaft, and connected to separate cranks.

According to another feature of the invention, a retractable mounting for a wheel or equivalent landing member on an aircraft comprises a tubular strut adapted to move angularly about a substantially horizontal pivot shaft in the aircraft, wherein the tubular strut forms a cylinder, and a piston therein is coupled to a crank on the, pivot shaft, the piston being moved axially within the tubular strut to move the latter bodily about its pivot. The tubular strut may form a cylinder in which fluid pressure acts on the piston, and also the cylinder of a telescopic shock' absorber. The tubular ,strut may be pivoted intermediate its ends, the part on one side of the pivot forming the cylinder for the retracting piston, and the part on the other side of the pivot forming the shock absorber cylinder. A locking device for retaining the mounting in at least one of its extreme positions may be released by the application of fluid pressure to rotate the mounting about its pivot.

The invention will now be described with reference to the accompanying drawings, in which:

Figure 1 is a section through the upperend of a shock absorberstrut for an aircraft landing gear, in which is incorporated the mechanism according to the invention, the section being taken on the line l-l of Figure 2;

Figure 2 is a section on a plane at right angle to that of Figure 1, through the same shock absorber strut;

Figure 3 is a section corresponding to Figure 2, of a modified arrangement;

Figure 4 is a corresponding section of a further arrangement; and

reduced scale, showing a shock absorber in vertical section attached to the rotating mechanism of Figure 4.

Referring to Figures 1 and 2, a tubular member i0 constituting a mounting fora wheel or equivalent landing member on an aircraft and forming at its lower part the cylinder ll of an oleo-pneumatic .shock absorber strut, is surrounded near its upper end, by a sleeve l2 formed with diametrically opposite hollow bosses l3, l4,

* the sleeve l2 being secured to the tubular member Figure 5 is a view similar to Figure 4 on a ill by a diametral bolt 15 (Figure 2), and by a plurality of dowel pins l3. The bolt l5 serves also to secure in position an internal partition l1 closing the upper end of the shock absorber cylinder ll. Passing through the two bosses l3, I4 is a pivot shaft l3 having flanged ends I! by which it may be secured by bolts through holes 21 to the aircraft structure, the pivot shaft It being divided to provide a space 22 bridged bytwo pins 23, 24 set eccentrically to the axis of the pivot shaft. These pins 23, 24 have each a central portion of greater diameter than their ends, and are screw threaded at each end. The

pivot shaft [3 is formed with holes 25 in each of its portions to receive the ends of the pins, the holes 25 being shouldered at 20, and the shoulders produced by the change in diameter of the pins are drawn up against the shoulders 28 by capnuts 21 screwed on to the ends of the pins and engaging with other shoulders formed by counterbored recesses 28 extending from the outer ends of the pivot shaft I3 co-axial with the holes 23. On the pin 23 is mounted a connectin rod 3|, the other end of which is secured by a gudgeon pin 32 too. piston 33 slidable in the part between the two pistons, and tends to urge them apart. Each of the pistons is provided with a sealing ring 42 which may be of the type described in the specification of British Patent No.

474,055, and similar sealing'rlngs 43, 44, 45 and 46, are provided to seal the end closure plug 38',- the partition I! and the sleeve l2 respectively. The pins 23 and 24 are disposed with their axes in a common diametral plane of the pivot shaft it, this plane being at an angle of substantially the retracting piston.

strut, and to the space 48 between the piston 33 and the partition I! for extending the strut. The fluid is supplied through the pivot shaft l8, each of the working spaces eing connected to a passage in one end of the said shaft. A stopped hole 49 in one part of the shaft I8 communiin the drawing, the upper end of the tubular cates with transverse bores 58 leading to a groove cut in the interior surface of the boss i3, and a passage 52 leading from this groove 5| is connected by piping 53 and a banjo connector 54 to an orifice 55 in the end closure plug 38, through which liquid passes into the space 41. A hole 56 passes right through the other part of the pivot shaft l8, to supply fluid to the space 48.

Thestem 31 projecting through the closure plug 38 is arranged to engage in a recess 51 in a i convenient portion of the aircraft structure when I the strut is in the extended position.

To retract the strut, fluid under pressure is supplied to the space 41 through the passages 49, 58, 5|, 52, 53, 54 and 55, this fluid causing the piston 36 to move inwardly, compressing the spring 4| and withdrawing the stem 31 from the recess 51. When the piston 36 has moved 3 far enough to release the stem 31 fully from the-recess 51, the rim of the piston engages with the face of the piston 33, the two pistons then moving together as one. Such inward movement 1 of the piston 33 is resisted by the connecting rod and can be accommodated only by turning of the strut about the axis of the pivot shaft l8,

, which increases the distance between the pin 23 and the closure plug 38. The strut turns through substantially a right angle to-the posij tion shown in chain-dotted lines in Figure 2, 1 and may be retained in the retracted position either by retaining the fluid in the space 41, or by a separate mechanical lock. The lowering or extending of the strut is effected by supplying fluid to the space 48by the passage 56, and releasing the fluid from the space 41, the stem 1 3! re-engaging with the recess 51 under the influence of the spring 4| when the strut is fully extended.

Figure 3 shows amodifled form of the invention providing for automatic control of ,locking devices at both the extreme positions of a strut, 1 by the fluid pressure performing the lowering 3 and retraction of the strut. The tubular member iii of the strut as in the arrangement shown in Figures 1 and 2 has a pivot shaft 18 passing through bosses on a sleeve 2 secured to the member by a bolt I5 and dowels l6, the part ll of the tubular member below the pivot shaft I8 forming the cylinder of a shock absorber strut, 1 whilst the part 84 above the pivot shaft houses In this arrangement a single piston 6| formed with a-stem 62 is cou- ,pled withlost motion to a connecting rod 63,

the gudgeon pin 64 being movable in slots 65 in the piston. The pins 66,61 joining the two parts of the pivot shaft l6 are on a diametral ;'plane of the pivot shaft at an angle of 60 to the axis of the tubular member "when .extended, and the connecting rod 63 is connected to the pin which is more remote from the head of the piston in that position. The stem 62 Q passes through the end closure plug 68 of the tubular member H), which plug 68 'has a seg- In the extended position, shown in full lines member engages a fixed abutment '12, and a spring latch 13 engages with the step II to maintain the unit' in position. In the retracted posi- 6| is fully withdrawn intothe tubular member,'

the end o f the stem 62 being substantially level with the main outer surface of the closure plug 68. To retract the strut, pressure liquid'is supplied through the passage 16 to the space 11 between the piston 6| and the partition H. The pressure acts on they piston 6|, flrst of all moving it through the lost motion allowed by the slots 65, duringwhich the stem 62 lifts the latch 13 clear of the step 1|, and, when the lost motion is taken up, causing the strut to turn about the pivot' shaft l8. retracted position, the stem 62 pushes back the latch 15, which springs outwardly when the stem has passed, and retains the latter in engagement with the abutment 14. The strut is brought into the extended position by supplying fluid under pressure to the space 18 between the piston 6| and the end closure plug 68, through supply passages corresponding to those shown in Figure 1 for supplying the space 41, the lost motion between-the piston and the connecting rod permitting the stem 62 to be withdrawn from its engagement with the latch 15 before any turning moment is applied to the strut.

In the arrangement shown in Figure 4, the piston 8| is on the same side of the pivot shaft l8 as is the shock absorber unit as shown in- Figure 5, the top closure plug 82 for the tubular member being immediately above the shaft I8.

The piston is connected by a connecting rod 83 to an eccentric pin 84 as in the previous examples, and the strut is retracted by admitting fluid under pressure to the space 85 between the piston 8| and the closure plug 82; The piston 8| forms the partition between the space 85 and the shock absorber cylinder H, and thus the retraction-of the strut causes compression of the resilient element of the shock absorber, so storing energy which may subsequently be utilised to return the strut to the extended position. With this arrangement, therefore, only one fluid connection to the strut is needed.

The arrangements shown in Figures 3 and 4 may be combined in a single strut, the piston 8| replacing the partition l1, and having its connecting rod coupled'to the pin 6'|. The pressure for retracting the strut then acts on the combined area of the pistons 6| and 8|, enabling a greater weight to be lifted by a given pressure, and the pressure acting on the piston for loweringthe strut is assisted by the stored energy in the shock absorber acting on the pis-.

Whilst the invention has been described as applied to an undercarriage. member of an aircraft, it will be understood that it maybe applied to a number of other uses. For exam-- ple, a permanently fitted lifting Jack on a motor vehicle may be mountedfor pivotal movement from ;a horizontal stored position to a vertical operative position by incorporating in its cylinder mechanism according to the present invenion.

What I claim is:

1. A retractable mounting for a wheel or equivalent member on a vehicle comprising a tubular As the strut approaches thevehicle passing through the tubular strut and having a crank portion, and a piston in the said tubular strut, and means connecting the piston with the crank portion of the pivot shaft, and means to move the piston axially within the tubular strut to move the strut bodily about its pivot and retract the strut.

2. A retractable mounting for a wheel or equivalent member on a vehicle comprising a tubular strut, a pivot shaft in the vehicle having a crank and about which the strut is adapted to move angularly from an operative to a-retracted position and vice versa, and a piston within said strut having a stem projecting beyond the end of the tubular strut to act as a locking device,.

a lost motion coupling connecting said piston to ed on the vehicle supporting said strut and about which the strut is adapted to-move angularly, a

two part piston within the tubular strut, a connection between one part of the piston and a stationary part of the vehicle, a locking stem on the second part of the piston adapted toenter into engagement with a part of the vehicle and means to introduce a fluid within said strut to move the second part of the piston axially to disengage the locking stem from the vehicle and thereafter engage the first part of the piston to move the strut bodily about its pivot.

4. A retractable mounting for a ground engaging member on a vehicle comprising a telesaid crank, and means to apply fluid pressure to either side ot said piston, so that the application of fluid pressure releases the locking device in either of the two positions of the strut, and thereafter rotates the strut to the other position.

3. A retractable mounting for a ground engaging member on a vehicle comprising a tubular strut, a pivot shaft adapted to be fixedly mountscopic shock absorber having a tubular portion on one end, a pivot shaft adapted to be fixedly mounted inrthe vehicle and having a crank por- .tion and supporting said shock absorber and about which the shock absorber'is adapted to move angularly. a piston within, said tubular portion of the shock absorber, means connecting the piston with said crank and means to move the piston axially to rotate the shock absorber bodily about its pivot.

. JOHN KEITH SIMPSON. 

